Retrospecti̇ve evaluati̇on of hyoi̇d bone posi̇ti̇on and head posture i̇n skeletal class I and class III females.

ERDOĞAN, M.F. (2019). Retrospective evaluation of hyoid bone position and head posture in Skeletal Class I and Class III females. İstanbul University, Faculty of Dentistry, Orthodontics Department. İstanbul. The aim of this retrospective study is to evaluate, head posture, hyoid bone position, their relationship and possible differences, as well as their interactions with other craniofacial and dentofacial structures on cephalometric radiographies of female adults. The material of this study consisted of preoperative and postoperative lateral cephalometric radiographies of skeletal Class I and Class III patients obtained from the I.U Faculty of Dentistry, Department of Orthodontics archieve. 130 patients included in our study consisted of 65 Class I and 65 Class III patients. Lateral cephalometric tracings and evaluations of the included patients were preformed on SİDEXİS program. As a result of cephalometric evaluation, a statistically significant difference was not observed between the head posture of Class I and Class III patients. Although not statistically significant, cervical colon was found to be more straight in Class III patients. No statistically significant differences observed between two groups in hyoid bone position vertically and anteroposteriorly, however hyoid bone is positioned away from the chin in Class III patients. When the relationship of the hyoid bone with anterior and posterior cranial bases, maxilla and mandibule was evaluated no statically significant difference was seen in sagittal and vertical position of the hyoid bone. Key Words: Hyoid Bone, Head Posture, Malocclusion, Class I, Class III